282 the canadian entomologist 



Explanation of Plate. 



Plate X. 



Figure 1, 5. th^lle, larva, — Distribution of the brachial nerve of the 1st thoracic 

 segment, c.gl., coxal ganglion; other lettering as on Plate XI, fig. 2. 



Figure 2, 5. thide, larva, — The under surface of the 3rd sympathetic ganglion, 

 showing a slender attached ganglion, g. 



Figure 3, S. thule, larva,- — Distribution of branches from the median and super- 

 ficial nerves of the 2nd thoracic segment to the main tracheae. 



Figure 4, S. thule, larva, — Distribution of the labial nerve at the junction of 

 the silk glands, a and b, ganglia arising from the labial nerve, l.n.; S. Gl., 

 silk glands reverted; Gl., a median gland lying below the silk gland; Sp.m., 

 muscles from the spinneret. 



Figure 5, Eacles imperialis, larva, — ^The vas deferens passing through a branch 

 of the additional nerve of the 8th segment. 



Figure 6, 6". thule, larva,- — The relation of the brachial nerve of the 3rd thoracic 

 segment with the peripheral sympathetic plexus. 



Figure 7, S. thule, larva,- — A portion of the rectal nerve arising from the lateral 

 ganglion of the rectum, l.g.r. 



Figure 8, 5. thule, larva,— Dorsal view of brain, or supraoesophageal ganglion 

 and its Nerves. Ant., antennal nerve; Ca. Gl., caudal ganglion; c. c, 

 crura cerebri ; Ce. Gl., cephalic ganglion; Ce. N., cephalic nerve; Fr. gl., 

 frontal ganglion; Fr. l.g., frontal ganglion of the labral nerve; 1., labral 

 nerve; m. br., mesal branch; L. S., lateral symathetic; 1, 2, 3, its ganglia; 

 S. ce.n., its cephalic nerve; S. 1. n., its lateral nerve; m., fibres to muscles; 

 m.gl., mesal ganglion; phbr., pharyngeal threads; p.f.g., post frontal ganglion; 

 R.N., recurrent nerve; s. br., sympathetic branches of the labral nerve, 1 

 and 2; S.gl., sympathetic ganglion; tr., threads to brancheoles; Tr., a trach- 

 eal; Opt., optic nerve. 



Figure 9, S. thule, larva, — Ventral view of the .suboesophageal ganglion and its 

 nerves. Br. N., brachial nerve; CC. crura cerebri; Li., labial nerve; 1. m., 

 l.n., strands from labral nerve; Md., mandible, and mandibular nerve; 

 m.ex., external branch, d.br., dorsal branch, v.br., ventral branch; Mx., 

 maxilla and maxillary nerve; s.c, suboesophageal commissure; s.gl., sub- 

 oesophageal ganglion; S.g. silk gland; sp.m., muscle of spinneret; 1st 

 Th., 1st thoracic ganglion; m., nerve fibres to muscles; mg., mesal ganglion 

 of labial nerves. 



Figure 10, S. thule, larva, — A general view of the nervous system. 



Figure 11, 5. thule, larva, — The alimentary canal, showing the silk gland of 

 one side and the malpighian tubes of one side. 



